Caring about something larger than yourself
This is not a knock-down argument, by any means. One person's modus ponens is another person's modus tollens, and some people, looking upon themselves, would prefer to forgo a sense of fairness and impartiality instead of choosing to care about strangers. But I, and many others, don't want to care only about our friends. We feel more loyalty to our aesthetics than our default feelings — and so the choice is easy.
Some use 'animal' as a derogatory, and may think that it's demeaning to try to see humans as animals instead of people. For me, the opposite is true, for the same reason that it's easier to feel compassion for a homeless dog than a homeless man — it helps me, to detach my automatic impulses to see other humans as competitors or allies or enemies, and just look at them the same way I would look at a kitten, as a pure creature possessing of the same wonder and innocence.
Connection to absolute-wellbeing heuristic of human social standing: Overcoming Bias : We Moderns Are Status-Drunk
Most light lord thing I've ever read.